Doses from external irradiation @ A. BouviLLe Er AL. 155 Table 7. Derived uncertainties, expressed in terms of the geometric standard deviation (GSD), in the annual doses from external irradiation for four representative communities of the Marshall Islands. Annual external whole-body dose (mGy) and uncertainty Majuro residents Kwajalein residents (south) Utrik community Rongelap Island community Year of exposure Year of birth Mean dose GSD Mean dose GSD Mean dose GSD Mean dose GSD 1948 1929 1947 1929 1947 1929 1947 1929 1953 1929 1953 1929 1953 0.016 0.021 — — 0.55 0.67 8.5 11 0.48 0.57 0.063 0.076 2.8 2.8 — — 1.6 1.6 1.2 1.2 2.9 2.9 2.8 2.8 4.6 6.0 0.039 0.047 0.60 0.72 15 19 1.3 1.5 0.24 0.29 2.0 2.0 2.8 2.8 1.9 1.9 1.3 1.3 1.7 1.7 1.9 2.0 0.011 0.014 0.35 0.42 0.34 0.41 120 160 0.56 0.67 1.2 1.4 2.8 2.8 2.9 2.9 1.8 1.8 1.3 1.3 1.4 1.4 1.3 1.3 1.8 2.4 0.62 0.75 0.37 0.45 1,600 2,000 0.48 0.58 2.7 3.3 2.8 2.8 2.7 2.7 1.8 1.8 1.3 1.3 2.8 2.8 1.5 1.5 1951 1952 1954 1956 1958 community, and the Utrik community) that represent the range of exposures across the Marshall Islands. The table applies to all years when testing gave rise to measurable fallout in the Marshall Islands. The derived GSDs, which range from 1.2 to 2.9, vary among years and amongatolls, essentially depending on the uncertainties assigned to E12 for each test and location. There is, however, very little dependence with age as the uncertainties for adults and for children have the same numerical values within a few percent. The external doses resulting from the tests detonated in 1954 were the largest of any year, regardless of the atoll or island. In contrast, the uncertainties of doses from tests in 1954 are the smallest because they are based on relatively good measurement data in comparison to other years when the doses were low andprimarily based on '’’Cs deposition estimates derived from interpolation of measurementdataat nearby atolls or, in some cases, meteorological modeling. Asa simplification for the purposes of estimating the risks of radiation-induced cancers (see Land et al. 2010), the uncertainties assigned to the annual doses from external irradiation to members of each community were given the same valuefor all years when testing took place. The GSDs assigned were based on the derived GSD estimates in the years in which the doses were mostsignificant. Overall, the GSDs were smallest in communities where the greatest dose resulted from the 1954 tests and highest in communities with the lowest doses from the 1954 tests. The derived GSDswere 1.2 for the Rongelap Island community, 1.5 for the Utrik community, and 1.8 for the Kwajalein and Majuro residents. Because the quality and availability of data were roughly the same for atolls and islands within each of four atoll groups (see Table 5), the GSDs were assumedto be the same for all communities within each group. These selected uncertainties apply to the annual doses received during the years when testing with measurable fallout occurred. In later years, the uncertainty would be larger as weathering andestimatedloss of '*’Cs from the soil profile, which can vary from one area of the island to another, could be substantial. However, the annual doses in the years without tests are lower by a factor of 100 or more than the doses received during the years of the tests; their GSDs have not been individually derived but assumed equalto those in the years assessed. SUMMARY AND CONCLUSION Annual doses from external irradiation resulting from fallout from regional nuclear weaponstesting have been estimated, for the first time, for all tests that resulted in measurable fallout and for all Marshallese alive at the time of nuclear testing (1946-1958), and at all 25 inhabited atolls. The methodology used to estimate the doses is based on test- and location-specific radiation survey data coupled with estimates of fallout TOAsat the inhabited atolls or on deposition density estimates of '*’Cs coupled with fallout TOAs. Both types of data are discussed in a companion paper (Becket al. 2010). For every test, the major part of the dose from external irradiation was received during thefirst year following the detonation. The most important tests with respect to external exposure were those of the Castle series conducted in 1954. Bravo was most important to the northern atolls, Yankee was more important to the mid-latitude atolls (Kwajalein and others), and Romeo and Koon were more important to the southern atolls (Majuro andothers). The total external doses to the populations ofall the inhabited atolls from all tests at Bikini and Enewetak varied over two orders of magnitude with the adult residents of the southern atolls receiving relatively low total external doses ranging from 5—22 mGyon average, the adults at the mid-latitude atolls receiving external doses of 22-59 mGy, while the residents of the northern